Single-cam and dual-cam compound archery bows have a power cam mounted on one or both ends of the bow limbs to control the draw force on the bowstring and the bending of the bow limbs as the bowstring is drawn. In single-cam bows, there is a power cam on the end of one bow limb with two let-out groves to facilitate let-out of bowstring as the bow is drawn, and a power take-up groove to take up a cable that can be anchored to the axle of a single groove idler wheel located on the opposite limb. In dual-cam bows, power cams are mounted on the ends of both limbs, with each including grooves or groove segments to control let-out of the bowstring on the opposing cam and power take-up grooves to take up cable that can be anchored at its opposing cam axle. More recently there have been hybrid cam systems that incorporate a mixture of both systems; there is a power cam on the end of one bow limb, and a two groove wheel on the end of the other bow limb to facilitate control or time take-up of a power cable at the power cam, and let-out of bowstring and control cables at the power cam as the bowstring is drawn. The power cam or cams may include a draw length control module adjustably and/or removably mounted on the power cam for adjusting the draw length of the bow.
In conventional bows of the described character having one or more adjustably or replaceably mounted draw length modules, adjustment and/or replacement of the module(s) can be made without concern for cable length because the power cable typically is anchored independently of its cam to an axle of the cam or wheel opposite its take-up and its effective length is not affected when draw length modules are changed to alter draw length. More recently there has been a new two-cam design where the power cable groove has both a let-out portion and a take-up portion on each cam. When modules are used to change draw length with this cam system, there is a problem with increasing cable slack as the draw length is decreased. A way to address this situation is to change power cables when the bow draw length is adjusted. A general object of the present disclosure is to provide a compound archery bow with draw length adjustment modules that automatically compensate for slackening that would otherwise occur in the power cable(s) as the draw length is adjusted.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A compound archery bow in accordance with one aspect of the present disclosure includes a bow handle having projecting limbs, and first and second pulleys mounted on the limbs for rotation around respective axes. A bowstring cable extends from a bowstring anchor through a bowstring let-out groove on the first pulley and then toward the second pulley. A first power cable extends from a first power cable anchor toward the second pulley, and a second power cable extends from the second pulley through a power cable take-up arrangement on the first pulley to a second power cable anchor on the first pulley. Draw of the bowstring cable away from the handle lets out bowstring cable from the bowstring let-out groove, rotates the first pulley around the first axis, and takes up the second power cable into the second power cable take-up arrangement on the first pulley. A set of at least first and second bowstring cable draw length adjustment modules is provided for alternate mounting on the first pulley to adjust draw length of the bowstring cable away from the handle. Each of the modules includes a first portion for mounting adjacent to the first axis, an intermediate portion that includes a power cable take-up groove that constitutes at least part of the power cable take-up arrangement on the first pulley, and a heel portion for mounting spaced from the first axis and adjacent to the power cable anchor such that the power cable take-up groove extends around the heel to a position adjacent to the power cable anchor. The heel is larger on one of the modules than on the other.
A compound archery bow in accordance with another aspect of the present disclosure includes a bow handle having projecting limbs, and first and second pulleys mounted on the limbs for rotation around respective axes. A bowstring cable extends from a bowstring anchor through a bowstring let-out groove on the first pulley and then toward the second pulley. A first pulley power cable let-out portion of a power cable groove extends a power cable from the first pulley toward the second pulley take-up portion of the power cable groove, and a second pulley power cable let-out portion of the power cable groove extends a power cable from the second pulley to a power cable take-up arrangement on the first pulley. Draw of the bowstring cable away from the handle lets out bowstring cable from the bowstring let-out groove, rotates the first pulley around the first axis as it lets out the first power cable and takes up the second power cable into the second power cable take-up arrangement on the first pulley and rotates the second pulley around the second axis as it lets out the second power cable and takes up the first power cable into the first power cable take-up arrangement on the second pulley. A set of at least first and second bowstring cable draw length adjustment modules is provided for alternate mounting on the pulleys to adjust draw length of the bowstring cable away from the handle. Each of the modules includes a first portion for mounting adjacent to the first axis, an intermediate portion that includes a power cable take-up groove that constitutes at least part of the power cable take-up arrangement on the first pulley, and a heel portion for mounting spaced from the first axis and adjacent to the power cable anchor such that the power cable take-up groove extends around the heel to a position adjacent to the power cable anchor. In accordance with this aspect of the present disclosure, the size varies from one set to another and becomes larger as the draw length becomes shorter.